SOLTI-1904 ACROPOLI TRIAL: efficacy of spartalizumab monotherapy across tumor-types expressing high levels of PD1 mRNA

Improved selection of cancer patients who are most likely to respond to immune checkpoint inhibitors remains an unmet clinical need. Recently, a positive correlation between levels of PD1 mRNA and clinical outcome in response to PD1 blockade across diverse tumor histologies has been confirmed in several datasets. ACROPOLI is a parallel cohort, non-randomized, phase II study that aims to evaluate the efficacy of the anti-PD1 immune checkpoint inhibitor spartalizumab as monotherapy in metastatic patients with solid tumors that express high levels of PD1 (cohort 1; n = 111). An additional cohort of 30 patients with tumors expressing low levels of PD1, where PD1/PD-L1 antibodies in monotherapy are standard treatment, will also be included (cohort 2). Primary end point is overall response rate in cohort 1. Considering previous data, we hypothesized that anti-PD1 monotherapy is effective across multiple cancer types in patients with PD1-high mRNA expressing tumors. Given these observations, ACROPOLI is a phase II study designed to study spartalizumab in this population. This article describes the SOLTI-1904 ACROPOLI phase II trial, `Efficacy of spartalizumab across multiple cancertypes in patients with PD1-highmRNA expressing tumors defined by a single and pre-specified cutoff.' The primary objective is to determine overall response rate (ORR) in the PD1-high population. Secondary objectives include other measures of clinical efficacy and evaluation of safety and tolerability. Spartalizumab has shown to have a manageable safety profile and preliminary clinical efficacy according to several phase I/II clinical trials [1-3].